source node correction

pyk/src/pyk/kcfg/kcfg.py

@@ -586,6 +586,7 @@ def log(message: str, *, warning: bool = False) -> None:
                 log(f'abstraction node: {node.id}')
 
             case Step(cterm, depth, next_node_logs, rule_labels, _):
+                node_id = node.id
                 next_node = self.create_node(cterm)
                 # Optimization for steps consists of on-the-fly merging of consecutive edges and can
                 # be performed only if the current node has a single predecessor connected by an Edge
@@ -596,12 +597,13 @@ def log(message: str, *, warning: bool = False) -> None:
                 ):
                     # The existing edge is removed and the step parameters are updated accordingly
                     self.remove_edge(in_edge.source.id, node.id)
+                    node_id = in_edge.source.id
                     depth += in_edge.depth
                     rule_labels = list(in_edge.rules) + rule_labels
                     next_node_logs = logs[node.id] + next_node_logs if node.id in logs else next_node_logs
-                self.create_edge(in_edge.source.id, next_node.id, depth, rule_labels)
+                self.create_edge(node_id, next_node.id, depth, rule_labels)
                 logs[next_node.id] = next_node_logs
-                log(f'basic block at depth {depth}: {node.id} --> {next_node.id}')
+                log(f'basic block at depth {depth}: {node_id} --> {next_node.id}')
 
             case Branch(branches, _):
                 branch_node_ids = self.split_on_constraints(node.id, branches)